Project Summary Millions of endoscopic nasal sinus surgeries are performed annually worldwide, yet the outcomes are often variable. One reason is that predicting functional outcomes (e.g. nasal airflow) based solely on CT or endoscopy can be difficult. The lack of an objective planning system results in ineffective disease management. For this proposal, a unique multidisciplinary team of clinicians, computer scientists, and engineers was assembled to develop a virtual endoscopic sinus surgery simulator that would simulate patient anatomy, reveal flow obstructions, and ultimately facilitate optimization of the outcome of surgical approaches for treatment of nasal obstruction and conductive olfactory loss. Using virtual reality, the surgeon can remove obstructive tissue virtually through a haptic (tactile and kinesthetic) feedback device. After each virtual surgery, changes in nasal airflow can be computed and displayed and the process reiterated until an optimal result is reached. A trial using this approach was performed on four patients as a proof of concept, and a normative range of air/odor flow based on 22 healthy controls was established. We will continue to improve the overall fidelity of our system (Aim 1) by incorporating feedback from clinicians and iterative innovation employing recent advances in computer science (image processing, volume visualization, haptic modeling, interface design). We will also perform non-interventional trials on 20 patients and focus on nasal obstruction related olfactory loss (Aim 2) and test the hypothesis that the virtual sinus surgery simulator can improve treatment outcomes to conductive olfactory loss. While this proposal is limited to the specific symptom of obstruction-related olfactory loss, but in the future the tool can be expanded to improve outcomes for more generalized nasal obstruction symptoms. Ultimately, developing and validating such a virtual surgical planning system will prove invaluable for future surgical treatment of nasal obstruction and has the potential to directly improve clinical practice and offer personalized medicine.